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Diffstat (limited to 'src/leveldb/helpers/memenv/memenv.cc')
-rw-r--r-- | src/leveldb/helpers/memenv/memenv.cc | 384 |
1 files changed, 0 insertions, 384 deletions
diff --git a/src/leveldb/helpers/memenv/memenv.cc b/src/leveldb/helpers/memenv/memenv.cc deleted file mode 100644 index 5879de1214..0000000000 --- a/src/leveldb/helpers/memenv/memenv.cc +++ /dev/null @@ -1,384 +0,0 @@ -// Copyright (c) 2011 The LevelDB Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. See the AUTHORS file for names of contributors. - -#include "helpers/memenv/memenv.h" - -#include "leveldb/env.h" -#include "leveldb/status.h" -#include "port/port.h" -#include "util/mutexlock.h" -#include <map> -#include <string.h> -#include <string> -#include <vector> - -namespace leveldb { - -namespace { - -class FileState { - public: - // FileStates are reference counted. The initial reference count is zero - // and the caller must call Ref() at least once. - FileState() : refs_(0), size_(0) {} - - // Increase the reference count. - void Ref() { - MutexLock lock(&refs_mutex_); - ++refs_; - } - - // Decrease the reference count. Delete if this is the last reference. - void Unref() { - bool do_delete = false; - - { - MutexLock lock(&refs_mutex_); - --refs_; - assert(refs_ >= 0); - if (refs_ <= 0) { - do_delete = true; - } - } - - if (do_delete) { - delete this; - } - } - - uint64_t Size() const { return size_; } - - Status Read(uint64_t offset, size_t n, Slice* result, char* scratch) const { - if (offset > size_) { - return Status::IOError("Offset greater than file size."); - } - const uint64_t available = size_ - offset; - if (n > available) { - n = available; - } - if (n == 0) { - *result = Slice(); - return Status::OK(); - } - - size_t block = offset / kBlockSize; - size_t block_offset = offset % kBlockSize; - - if (n <= kBlockSize - block_offset) { - // The requested bytes are all in the first block. - *result = Slice(blocks_[block] + block_offset, n); - return Status::OK(); - } - - size_t bytes_to_copy = n; - char* dst = scratch; - - while (bytes_to_copy > 0) { - size_t avail = kBlockSize - block_offset; - if (avail > bytes_to_copy) { - avail = bytes_to_copy; - } - memcpy(dst, blocks_[block] + block_offset, avail); - - bytes_to_copy -= avail; - dst += avail; - block++; - block_offset = 0; - } - - *result = Slice(scratch, n); - return Status::OK(); - } - - Status Append(const Slice& data) { - const char* src = data.data(); - size_t src_len = data.size(); - - while (src_len > 0) { - size_t avail; - size_t offset = size_ % kBlockSize; - - if (offset != 0) { - // There is some room in the last block. - avail = kBlockSize - offset; - } else { - // No room in the last block; push new one. - blocks_.push_back(new char[kBlockSize]); - avail = kBlockSize; - } - - if (avail > src_len) { - avail = src_len; - } - memcpy(blocks_.back() + offset, src, avail); - src_len -= avail; - src += avail; - size_ += avail; - } - - return Status::OK(); - } - - private: - // Private since only Unref() should be used to delete it. - ~FileState() { - for (std::vector<char*>::iterator i = blocks_.begin(); i != blocks_.end(); - ++i) { - delete [] *i; - } - } - - // No copying allowed. - FileState(const FileState&); - void operator=(const FileState&); - - port::Mutex refs_mutex_; - int refs_; // Protected by refs_mutex_; - - // The following fields are not protected by any mutex. They are only mutable - // while the file is being written, and concurrent access is not allowed - // to writable files. - std::vector<char*> blocks_; - uint64_t size_; - - enum { kBlockSize = 8 * 1024 }; -}; - -class SequentialFileImpl : public SequentialFile { - public: - explicit SequentialFileImpl(FileState* file) : file_(file), pos_(0) { - file_->Ref(); - } - - ~SequentialFileImpl() { - file_->Unref(); - } - - virtual Status Read(size_t n, Slice* result, char* scratch) { - Status s = file_->Read(pos_, n, result, scratch); - if (s.ok()) { - pos_ += result->size(); - } - return s; - } - - virtual Status Skip(uint64_t n) { - if (pos_ > file_->Size()) { - return Status::IOError("pos_ > file_->Size()"); - } - const size_t available = file_->Size() - pos_; - if (n > available) { - n = available; - } - pos_ += n; - return Status::OK(); - } - - private: - FileState* file_; - size_t pos_; -}; - -class RandomAccessFileImpl : public RandomAccessFile { - public: - explicit RandomAccessFileImpl(FileState* file) : file_(file) { - file_->Ref(); - } - - ~RandomAccessFileImpl() { - file_->Unref(); - } - - virtual Status Read(uint64_t offset, size_t n, Slice* result, - char* scratch) const { - return file_->Read(offset, n, result, scratch); - } - - private: - FileState* file_; -}; - -class WritableFileImpl : public WritableFile { - public: - WritableFileImpl(FileState* file) : file_(file) { - file_->Ref(); - } - - ~WritableFileImpl() { - file_->Unref(); - } - - virtual Status Append(const Slice& data) { - return file_->Append(data); - } - - virtual Status Close() { return Status::OK(); } - virtual Status Flush() { return Status::OK(); } - virtual Status Sync() { return Status::OK(); } - - private: - FileState* file_; -}; - -class NoOpLogger : public Logger { - public: - virtual void Logv(const char* format, va_list ap) { } -}; - -class InMemoryEnv : public EnvWrapper { - public: - explicit InMemoryEnv(Env* base_env) : EnvWrapper(base_env) { } - - virtual ~InMemoryEnv() { - for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){ - i->second->Unref(); - } - } - - // Partial implementation of the Env interface. - virtual Status NewSequentialFile(const std::string& fname, - SequentialFile** result) { - MutexLock lock(&mutex_); - if (file_map_.find(fname) == file_map_.end()) { - *result = NULL; - return Status::IOError(fname, "File not found"); - } - - *result = new SequentialFileImpl(file_map_[fname]); - return Status::OK(); - } - - virtual Status NewRandomAccessFile(const std::string& fname, - RandomAccessFile** result) { - MutexLock lock(&mutex_); - if (file_map_.find(fname) == file_map_.end()) { - *result = NULL; - return Status::IOError(fname, "File not found"); - } - - *result = new RandomAccessFileImpl(file_map_[fname]); - return Status::OK(); - } - - virtual Status NewWritableFile(const std::string& fname, - WritableFile** result) { - MutexLock lock(&mutex_); - if (file_map_.find(fname) != file_map_.end()) { - DeleteFileInternal(fname); - } - - FileState* file = new FileState(); - file->Ref(); - file_map_[fname] = file; - - *result = new WritableFileImpl(file); - return Status::OK(); - } - - virtual bool FileExists(const std::string& fname) { - MutexLock lock(&mutex_); - return file_map_.find(fname) != file_map_.end(); - } - - virtual Status GetChildren(const std::string& dir, - std::vector<std::string>* result) { - MutexLock lock(&mutex_); - result->clear(); - - for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){ - const std::string& filename = i->first; - - if (filename.size() >= dir.size() + 1 && filename[dir.size()] == '/' && - Slice(filename).starts_with(Slice(dir))) { - result->push_back(filename.substr(dir.size() + 1)); - } - } - - return Status::OK(); - } - - void DeleteFileInternal(const std::string& fname) { - if (file_map_.find(fname) == file_map_.end()) { - return; - } - - file_map_[fname]->Unref(); - file_map_.erase(fname); - } - - virtual Status DeleteFile(const std::string& fname) { - MutexLock lock(&mutex_); - if (file_map_.find(fname) == file_map_.end()) { - return Status::IOError(fname, "File not found"); - } - - DeleteFileInternal(fname); - return Status::OK(); - } - - virtual Status CreateDir(const std::string& dirname) { - return Status::OK(); - } - - virtual Status DeleteDir(const std::string& dirname) { - return Status::OK(); - } - - virtual Status GetFileSize(const std::string& fname, uint64_t* file_size) { - MutexLock lock(&mutex_); - if (file_map_.find(fname) == file_map_.end()) { - return Status::IOError(fname, "File not found"); - } - - *file_size = file_map_[fname]->Size(); - return Status::OK(); - } - - virtual Status RenameFile(const std::string& src, - const std::string& target) { - MutexLock lock(&mutex_); - if (file_map_.find(src) == file_map_.end()) { - return Status::IOError(src, "File not found"); - } - - DeleteFileInternal(target); - file_map_[target] = file_map_[src]; - file_map_.erase(src); - return Status::OK(); - } - - virtual Status LockFile(const std::string& fname, FileLock** lock) { - *lock = new FileLock; - return Status::OK(); - } - - virtual Status UnlockFile(FileLock* lock) { - delete lock; - return Status::OK(); - } - - virtual Status GetTestDirectory(std::string* path) { - *path = "/test"; - return Status::OK(); - } - - virtual Status NewLogger(const std::string& fname, Logger** result) { - *result = new NoOpLogger; - return Status::OK(); - } - - private: - // Map from filenames to FileState objects, representing a simple file system. - typedef std::map<std::string, FileState*> FileSystem; - port::Mutex mutex_; - FileSystem file_map_; // Protected by mutex_. -}; - -} // namespace - -Env* NewMemEnv(Env* base_env) { - return new InMemoryEnv(base_env); -} - -} // namespace leveldb |